Computer security authentication systems are used to limit login and usage of computer resources to persons possessing a valid user credential, such as a valid security token. A security token provides a similar function for a computer as car keys provide for an automobile. However, unlike an automobile, which requires keys to start an engine, current computer systems typically must already be powered on and operating in order to validate a token using an authentication system. For example, after a power-on event, some amount of time elapses before the security system is loaded, running, and can begin limiting access. Thus, such systems have a period of vulnerability if an unauthorized user is able to modify the power-on and boot-up process to disable or tamper with the authentication system before it becomes fully operative.